Horizontal Pod Autoscaling

Collectors managed by the OpenTelemetry Operator have built-in support for horizontal pod autoscaling (HPA). HPA increases or decreases the number of replicas (copies) of your Kubernetes pods, based on a set of metrics. These metrics are typically CPU and/or memory consumption.

Having the OpenTelemetry Operator manage HPA functionality for the Collector means that you don’t have to create a separate Kubernetes HorizontalPodAutoscaler resource for autoscaling your Collector.

Since HPA only applies to StatefulSets and Deployments in Kubernetes, make sure that your Collector’s spec.mode is either deployment or statefulset.

To configure HPA, you must first define your resource requests and limits by adding a spec.resources configuration to your OpenTelemetryCollector YAML:

resources:  limits:  cpu: 100m  memory: 128Mi  requests:  cpu: 100m  memory: 64Mi 

The limits configuration specifies the maximum memory and CPU values. In this case, those limits are 100 millicores (0.1 core) of CPU, and 128Mi (mebibytes, where 1 mebibyte == 1024 kilobytes) of RAM.

The requests configuration specifies the minimum guaranteed amount of resources allocated for the container. In this case, the minimum allocation is 100 millicores of CPU and 64 mebibytes of RAM.

Next, you configure the autoscaling rules by adding an spec.autoscaler configuration to the OpenTelemetryCollector YAML:

autoscaler:  minReplicas: 1  maxReplicas: 2  targetCPUUtilization: 50  targetMemoryUtilization: 60 

Putting it all together, the start of the OpenTelemetryCollector YAML should look something like this:

apiVersion: opentelemetry.io/v1beta1 kind: OpenTelemetryCollector metadata:  name: otelcol  namespace: opentelemetry spec:  mode: statefulset  image:  otel/opentelemetry-collector-contrib:v0.139.0  serviceAccount: otelcontribcol  autoscaler:  minReplicas: 1  maxReplicas: 2  targetCPUUtilization: 50  targetMemoryUtilization: 60  resources:  limits:  cpu: 100m  memory: 128Mi  requests:  cpu: 100m  memory: 64Mi 

Once the OpenTelemetryCollector is deployed to Kubernetes with HPA enabled, the Operator creates a HorizontalPodAutoscaler resource for your Collector in Kubernetes. You can check this by running

kubectl get hpa -n <your_namespace>

If everything worked as expected, here is what the output of the command should look like:

NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE otelcol-collector OpenTelemetryCollector/otelcol memory: 68%/60%, cpu: 37%/50% 1 3 2 77s 

To get more detailed information, you can describe your HPA resource by running

kubectl describe hpa <your_collector_name> -n <your_namespace>

If everything worked as expected, here is what the output of the command should look like:

Name: otelcol-collector Namespace: opentelemetry Labels: app.kubernetes.io/benchmark-test=otelcol-contrib app.kubernetes.io/component=opentelemetry-collector app.kubernetes.io/destination=dynatrace app.kubernetes.io/instance=opentelemetry.otelcol app.kubernetes.io/managed-by=opentelemetry-operator app.kubernetes.io/name=otelcol-collector app.kubernetes.io/part-of=opentelemetry app.kubernetes.io/version=0.126.0 Annotations: <none> CreationTimestamp: Mon, 02 Jun 2025 17:23:52 +0000 Reference: OpenTelemetryCollector/otelcol Metrics: ( current / target ) resource memory on pods (as a percentage of request): 71% (95779498666m) / 60% resource cpu on pods (as a percentage of request): 12% (12m) / 50% Min replicas: 1 Max replicas: 3 OpenTelemetryCollector pods: 3 current / 3 desired Conditions: Type Status Reason Message ---- ------ ------ ------- AbleToScale True ReadyForNewScale recommended size matches current size ScalingActive True ValidMetricFound the HPA was able to successfully calculate a replica count from memory resource utilization (percentage of request) ScalingLimited True TooManyReplicas the desired replica count is more than the maximum replica count Events: Type Reason Age From Message ---- ------ ---- ---- ------- Warning FailedGetResourceMetric 2m (x4 over 2m29s) horizontal-pod-autoscaler unable to get metric memory: no metrics returned from resource metrics API Warning FailedGetResourceMetric 89s (x7 over 2m29s) horizontal-pod-autoscaler No recommendation Normal SuccessfulRescale 89s horizontal-pod-autoscaler New size: 2; reason: memory resource utilization (percentage of request) above target Normal SuccessfulRescale 59s horizontal-pod-autoscaler New size: 3; reason: memory resource utilization (percentage of request) above target